1. Field of the Invention
The present invention relates to wireless communications, and more particularly, to a method and apparatus for optimum scheduling in a wireless multiple access system.
2. Related Art
Wireless communication systems are widely spread all over the world to provide various types of communication services such as voice or data. In general, the wireless communication system is a multiple access system capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmission power, etc.). Examples of the multiple access system include a code division multiple access (CDMA) system, a frequency division multiple access (FDMA) system, a time division multiple access (TDMA) system, an orthogonal frequency division multiple access (OFDMA) system, a single carrier frequency division multiple access (SC-FDMA) system, etc.
Time-division multiple-access (TDMA) and code division multiple-access (CDMA) have been intensively studied for more than last three decades, and have been serving as the major multiple-access schemes for the second and the third generation wireless cellular systems, respectively. Recently, the fourth generation wireless cellular system has started to be deployed worldwide, for which the frequency-division multiple-access (FDMA) serves in the form of discrete Fourier transform-spread orthogonal frequency-division multiplexing, a.k.a., single-carrier FDMA.
Since the primary performance limiting factor of a CDMA system is multiple-access interference (MAI), a lot of research has been conducted to mitigate the detrimental effect of the MAI through system parameter optimizations. At the transmitter side, signature sequences have long been identified as important design parameters and hence optimized under various criteria.